1) International Center for Young Scientists, National Institute for Materials Science2) Advanced Materials Laboratory, National Institute for Materials Science3) Department of Chemistry, Nagaoka University of Technology

In this study, we examined the temperature dependence of the second-harmonic (SH) intensity and Raman shift in the langasite-type Ba3Ga2Ge4O14 (BGG) and Na2CaGe6O14 (NCG) crystalline phases. The SH intensity curves revealed an anomalous temperature behavior around 370°C and 270°C in the BGG and NCG phases, respectively. Furthermore, as a result from the Raman spectral measurement, it was suggested that the anomaly observed in the lagasite-type phases originated in the A-site.